Narrative:

We were en route from tys to gso. There were numerous strong thunderstorms along the route associated with a passing frontal system. We were cleared to traks intersection to begin our arrival into gso. I was flying with a new copilot who had flown only 4-5 previous trips on the airplane. ZTL (132.97) cleared us to descend to FL240, however, the copilot entered the wrong altitude in the altitude selector which directed our descent path towards FL230. At approximately FL235 ZTL questioned our altitude and the copilot responded that we were descending to FL230. Center instructed us to climb immediately to FL240 and advised us of traffic at FL230 and its location relative to ours. I executed an immediate climb to FL240. It is normal operating procedure for the copilot to enter the altitude in the altitude selector when given an altitude change by ATC. He then repeats the altitude to ATC, then repeats it again to the captain. On this occasion he made a mistake when entering the altitude in the selector and due to existing conditions (WX and high workload) I was unaware of the mistake until we were advised by center. At the time of the occurrence, I was displaying WX radar on the mfd. I believe this situation may have been avoided if: 1) TCASII had been displayed along with WX radar. 2) copilot had more exposure to this aircraft. There was an advisory from the TCASII after we had begun the climb to FL240. According to ZTL supervisor, the traffic was 3.8 NM away at FL230.

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Original NASA ASRS Text

Title: FLC OF A CPR JET OVERSHOT ALT ON DSCNT ARR RESULTING IN ARTCC RADAR CTLR INTERVENTION IN ORDER TO AVOID A POSSIBLE CONFLICT WITH OTHER TFC 1000 FT BELOW. THE FO INADVERTENTLY HAD SET THE ALT SELECTOR TO 1000 FT BELOW ASSIGNED.

Narrative: WE WERE ENRTE FROM TYS TO GSO. THERE WERE NUMEROUS STRONG TSTMS ALONG THE RTE ASSOCIATED WITH A PASSING FRONTAL SYS. WE WERE CLRED TO TRAKS INTXN TO BEGIN OUR ARR INTO GSO. I WAS FLYING WITH A NEW COPLT WHO HAD FLOWN ONLY 4-5 PREVIOUS TRIPS ON THE AIRPLANE. ZTL (132.97) CLRED US TO DSND TO FL240, HOWEVER, THE COPLT ENTERED THE WRONG ALT IN THE ALT SELECTOR WHICH DIRECTED OUR DSCNT PATH TOWARDS FL230. AT APPROX FL235 ZTL QUESTIONED OUR ALT AND THE COPLT RESPONDED THAT WE WERE DSNDING TO FL230. CTR INSTRUCTED US TO CLB IMMEDIATELY TO FL240 AND ADVISED US OF TFC AT FL230 AND ITS LOCATION RELATIVE TO OURS. I EXECUTED AN IMMEDIATE CLB TO FL240. IT IS NORMAL OPERATING PROC FOR THE COPLT TO ENTER THE ALT IN THE ALT SELECTOR WHEN GIVEN AN ALT CHANGE BY ATC. HE THEN REPEATS THE ALT TO ATC, THEN REPEATS IT AGAIN TO THE CAPT. ON THIS OCCASION HE MADE A MISTAKE WHEN ENTERING THE ALT IN THE SELECTOR AND DUE TO EXISTING CONDITIONS (WX AND HIGH WORKLOAD) I WAS UNAWARE OF THE MISTAKE UNTIL WE WERE ADVISED BY CTR. AT THE TIME OF THE OCCURRENCE, I WAS DISPLAYING WX RADAR ON THE MFD. I BELIEVE THIS SIT MAY HAVE BEEN AVOIDED IF: 1) TCASII HAD BEEN DISPLAYED ALONG WITH WX RADAR. 2) COPLT HAD MORE EXPOSURE TO THIS ACFT. THERE WAS AN ADVISORY FROM THE TCASII AFTER WE HAD BEGUN THE CLB TO FL240. ACCORDING TO ZTL SUPVR, THE TFC WAS 3.8 NM AWAY AT FL230.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.